JP3348736B2 - Video camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic focusing apparatus and method suitable for use in a video camera or the like.

[0002]

2. Description of the Related Art For example, in a video camera, when a still subject is photographed in an auto-focus mode, if an object crosses in front of the camera in the middle of the photograph, the focus follows the camera and the focus shifts. There is. Also, when there are multiple objects before and after, in auto focus mode, it is not clear which is in focus,
There was something contrary to the photographer's will.

In such a case, if a photograph is taken in the manual focus mode, the focus can be adjusted to a desired subject. However, if the resolution of the viewfinder is not sufficient, it is impossible for the photographer to perform manual focusing with high accuracy. That is, a video camera using a liquid crystal viewfinder,
In a video camera for a DTV or the like, it is impossible to perform perfect focusing by manual focusing because the resolution of a finder is insufficient.

On the other hand, in a state where the photographer has roughly adjusted the focus by manual focusing, the mode is switched to the auto focus mode to accurately focus on the target object, and then switched to the manual focus mode again. Can be solved. However, performing such an operation during photographing cannot be easily performed, particularly because the operation is performed while observing the viewfinder.

[0005] In addition, an apparatus has been implemented to switch to the auto-focus mode only while one operation unit is being operated. However, it takes about one second to complete auto-focusing. Since the time is not constant, there is a risk of erroneous operation. Also, the operation of such an operation unit is complicated. The present application has been made in view of such a point.

[0006]

The problem to be solved is that the conventional switching between manual focus and auto focus is not appropriate, and the desired switching cannot be easily performed.

[0007]

According to a first aspect of the present invention, there is provided a viewfinder having an insufficient resolution with respect to a captured image.
In a video camera provided with an indexer, a manual focus means (manual focus ring 7) and an auto focus means (focus processing circuit 10, A / A
D conversion circuit 11) and the manual focus unit
Operation detection means (focuser) for detecting whether or not operation is in progress
And a sling counter 8).
Based on the force, when the manual focus unit is stopped for a predetermined time or more, the auto focus unit is automatically driven only once, and the manual focus is resumed.
The video camera is provided with control means (processing microcomputer 9) for returning .

[0008] A second means according to the present invention is the above-mentioned viewfinder.
The viewfinder is a liquid crystal viewfinder.
A video camera according to the first means .

[0009]

[0010]

According to this, the auto focus is automatically driven after the manual focus is operated.
A complicated operation is not required, and a desired focusing can always be performed accurately.

[0011]

FIG. 1 shows a main part of a video camera according to the present invention.
FIG .

In FIG. 1, image light is incident on a CCD 2 through a lens system including a focus lens 1. The video signal converted by the CCD 2 is taken out to an output terminal 6 through a sample hold circuit 3, an AGC circuit 4, and a video signal processing circuit 5.

Reference numeral 7 denotes a manual focus ring for performing a manual focus operation. The rotation of the ring 7 is controlled by a focus ring counter 8 using a pulse plate or the like.
, And the detected value is supplied to the processing microcomputer 9.

Further, an output signal (luminance signal) of the AGC circuit 4 is supplied to a focus processing circuit 10, and, for example, a contrast value is detected. This value is the A / D conversion circuit 1
1 to the processing microcomputer 9.

A control signal processed by the processing microcomputer 9 is supplied to a focus driver 12, and a focus motor 13 linked to the focus lens 1 is driven. Thus, for example, a control signal corresponding to the value detected by the counter 8 is formed, and the manual focus is controlled. In addition, a control signal is formed so that the value from the conversion circuit 11 increases, and autofocus control is performed.

In the processing microcomputer 9, processing (autofocus method) is executed according to a flowchart described below. This flowchart is provided as a part of the main routine of the video camera device.

In FIG. 2, it is determined in step [1] whether or not the focus ring 7 is operating. When the operation is being performed (Yes), the end flag is set to 0 in step [2], and the timer is reset to 0. Further, the AF flag is set to 0 in step [3].

If the operation is not being performed in step [1] (No), the timer is incremented in step [4]. Further, in step [5], it is determined whether or not the value of the timer is larger than a certain value. If not so (NO), the AF flag is set to 0 in step [6].

If it is larger in step [5] (Yes), it is determined in step [7] whether the end flag is 1 or not. Here, when it is 1 (yes), step [6]
Proceed to If the end flag is not 1 in step [7] (No), the AF flag is set to 1 in step [8].
To be.

Further steps

In [9], it is determined whether the AF flag is 0 or not. If it is 0 (yes), the manual focus mode is set in step [10]. Then, in step [11], other processing of the main routine is performed.

Steps

If the AF flag is 1 in [9] (No), the auto focus mode is set in step [12]. Further, in step [13], it is determined whether or not the auto focus is completed. If the process has not been completed (No), the process directly proceeds to step [11]. If the autofocus is completed in step [13] (Yes), the end flag is set to 1 in step [14], and the process proceeds to step [11].

[0022] Thus, in the apparatus described above, the operation of the manual focus is detected, after the manual focusing is performed, when it is stopped for a predetermined time or more, its
Is controlled to drive the auto focus only once from the stopped position .

According to the apparatus and method described above, the auto focus is automatically driven after the manual focus is operated, so that a complicated operation is not required and a desired focus can always be accurately adjusted. Things.

Thus, for example, when a still subject is photographed, even if there is an object crossing in front of the camera, the focus will not be shifted. Even when there are a plurality of objects before and after, it is possible to perform focusing according to the intention of the photographer. Further, perfect focus adjustment can be performed even with a video camera using a liquid crystal viewfinder or a video camera for HDTV.

[0025]

According to the present invention, since the auto focus is automatically driven after the manual focus is operated, a complicated operation is not required and the desired focus can always be accurately adjusted. became.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an example of an autofocus device according to the present invention.

FIG. 2 is a flowchart of an example of an autofocus method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Focus lens 2 CCD 3 Sample hold circuit 4 AGC circuit 5 Video signal processing circuit 6 Output terminal 7 Manual focus ring 8 Focus ring counter 9 Processing microcomputer 10 Focusing processing circuit 11 A / D conversion circuit 12 Focus driver 13 Focus motor

Claims (2)

(57) [Claims] 1. Insufficient resolution for a captured image
Video camera equipped with a special viewfinder, a manual focus unit, an auto focus unit, and a check whether the manual focus unit is operating.
And a movement detecting means for detecting that, based on the output of said movement detecting means, when stopping for a predetermined time or more automatically allowed only drives the automatic focusing means once the manual focusing means, again Ma
A video camera provided with control means for returning to a focus mode. 2. The view finder according to claim 1, wherein the view finder is a liquid crystal viewer.
2. The video camera according to claim 1, wherein the video camera
Mela.